My BC guy, we have know had for over a year has suddenly started to attack other dogs, not the same breed any breed. He has always been socialised with other dogs since we got him plays Daily with friends dogs. We have a busy family 2young children who love him and he loves them, never attacked or bite them. We go on weekly massive works, he has daily runs every night. He obeys when he feels like it, more to my husband when he has his fav toy. Apart from him being really giddy we have not had a problem until recently, were he is attacking some dogs? This is worrying us as we enjoy our family days out were guy is a big part of them, we feel nervous around other dogs and know they pick up on this. We have been told of two different things of 2 different dog trainers that BC don't need as much exercise daily but need third mind occupied more and the other said they do need lots of exercise. We are confused about this, guy has lots of exercise and panty of toys. If any one could give me an insight to why or even mind occupying activities, they would be very much appreciated. Thank you.